The present invention relates to an exterior rearview mirror for mounting on a vehicle and, more particularly, to an exterior rearview assembly which includes a housing and a reflective element supported in the housing by a support bracket.
Conventional exterior rearview mirror assemblies include a housing and a reflective element which are often supported in the housing by a mirror support bracket. In fixed position assembles, the mirror support bracket is secured to the housing on one end and secured to the vehicle on the other end. In break-away assemblies, the mirror support bracket is fixed at one end to the housing and then pivotally mounted to a mounting bracket at the other end, which in turn is mounted to the vehicle.
Regardless of the type of mounting, present mounting brackets and/or mirror support brackets typically comprise glass filled nylon or polyester. Both these materials have high moduli of elasticity. As a result, these mounting brackets and mirror support brackets have high stiffness and, generally, exhibit good vibration performance. However, in larger mirror assemblies or in mirror assemblies that are extended further from the vehicle, for example in towing mirrors, the glass filled nylon and polyester mirror support brackets and/or mounting brackets add considerable weight to the assemblies. Consequently, the dampening characteristics of these assemblies decrease and, therefore, exhibit increased vibration. In some cases, the support and mounting bracket comprise a metal material, such as aluminum die cast or zinc die cast. Again, the weight of these assemblies is increased and, as a result, the mirror assemblies exhibit increased vibration, which degrades the quality of images reflected by the reflective element. Furthermore, increased vibration may increase the wear and tear on the component parts supported on the exterior rearview mirror.
Consequently there is a need for an exterior rearview mirror assembly that is lighter and yet provides sufficient stiffness for improved operation when mounted the vehicle.